JPH054998Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a foam molding machine with a mold used for manufacturing thermoplastic synthetic resin foam molded products such as plastic foam. This invention relates to a pressure regulating valve that can adjust the supply of heated steam.

[Prior art]

To manufacture foam molded products, expandable thermoplastic resin particles (beads) are pre-foamed using a mold, or are filled into the mold without pre-foaming, heated and molded, and then cooled and released from the mold. It is common to dry it afterwards.

In this conventional foam molding, a steam chest method is often used in which beads are filled into a mold, heated with steam to perform foam molding, cooled with low-temperature cooling water such as tap water, and then released from the mold.

However, in foam molding equipment made using this method, the volume of the heating steam chamber is constant, so the steam temperature in the chamber is directly proportional to the steam pressure, so the steam pressure is adjusted using a pressure regulating valve to adjust the steam temperature. It is being said. That is, as shown in FIG. 3, this conventional pressure regulating valve has two valves, an on-off valve device V ₁ and a pressure reducing valve device V ₂ , arranged adjacent to each other at right angles to each other in the steam supply passage A. The valve device _V2 is provided with an adjustment nut B for adjusting the opening degree of the pressure reducing valve body, so that the pressure can be regulated.

[Problem that the invention attempts to solve]

However, when the steam pressure is adjusted using this valve device, the pressure regulating mechanism is kept constant, so only a constant amount of steam can be supplied at all times. This process took around 10 seconds, and there was a limit for each molding cycle, making it impossible to increase productivity. Furthermore, since the piping system was located within the frame, it was difficult to adjust the steam supply using the pressure regulating valve.

The present invention attempts to eliminate these conventional drawbacks by making it easier to degas the beads, significantly shortening the steam supply time, speeding up the molding operation, improving production efficiency, and adjusting the The purpose of this valve is to provide a pressure regulating valve that does not require frequent operation, can be automatically adjusted, has an inexpensive configuration without complicated restrictions in terms of equipment, is safe, and can perform stable foam molding operations. be.

[Means for solving problems]

The present invention uses a heating steam source and a metal mold to supply heated steam to the chamber of a foam mold of a foam molding machine that performs foam molding by steam heating after filling a mold with expandable thermoplastic resin particles. A pressure regulating valve consisting of a pressure regulating part and an opening/closing part provided in a steam supply path communicating with the mold, and the pressure regulating part includes a piston provided on the valve shaft of the opening/closing valve, and a spring connecting the piston. It consists of a cylinder biased in one direction and slidably disposed, a flow path that communicates both cylinder chambers partitioned by a piston in the cylinder, and a regulating valve that opens and closes the flow path, and the valve A connecting member into which a shaft is slidably fitted, a supporting shaft which is slidably inserted into the connecting member, and a diaphragm which operates the regulating valve in the flow path by the supporting shaft, and this One of the pressure regulating chambers partitioned by a diaphragm is connected to a pressure regulating air source through piping, and the other pressure regulating chamber is connected to a secondary steam piping connected to the mold, and the other pressure regulating chamber is connected to a secondary steam piping connected to the mold. is connected to an air source P via a valve opening/closing air piping, and an air exhaust hole is provided in the cylinder chamber, and the opening/closing valve is configured as a globe valve. It is a pressure valve.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. A pair of male mold 1 and female mold 2 having chambers 1 ₁ and 2 ₁ are formed by an inner plate with ventilation holes and a back plate. Configure the mold as
The molds are respectively attached to frames that face each other so that they can be freely approached and separated so that a cavity portion is formed between the two molds 1 and 2, and foamable thermoplastic resin particles (beads) are placed in the molds. As a mold for foam molding of a foam molding machine that performs foam molding by steam heating after filling,
A steam supply pipe 3 for supplying heated steam from a heating steam source S to the chamber parts 1 ₁ , 2 ₁ is connected and provided, and a pressure regulating part 4 communicating with an air source P is provided in the steam supply pipe 3 . A pressure regulating valve consisting of an on-off valve 5 and an on-off valve 5 is interposed therebetween. The pressure regulating section 4 also includes a piston 12 provided on the valve shaft 51 of the on-off valve 5, and a piston 12 provided on the valve shaft ₅₁ of the on-off valve 5.
2 is biased in one direction by a spring 15 so as to be slidably disposed, and a flow path 17 that communicates both cylinder chambers 11 ₁ and 11 ₂ defined by a piston 12 in the cylinder 11, a connecting member 23 consisting of a regulating valve 14 that opens and closes the passage 17 and into which the valve shaft 5 ₁ is slidably fitted; and the connecting member 2
3, a support shaft 22 slidably inserted into the support shaft 22;
A diaphragm 13 is provided to operate the regulating valve 14 in the flow passage 17 toward and away from the flow passage 17, and one pressure regulating chamber 13 2 of the pressure regulating chambers 13 ₁ and 13 ₂ divided by the diaphragm 13 is connected to the pressure regulating chamber 13 ₂ by the piping 7. The other pressure regulating chamber 13 ₁ is connected to the secondary steam pipe 6 connected to the molds 1 and 2, and the cylinder 1
The cylinder chamber 11 ₁ of 1 is connected to the air source P via the valve opening/closing air piping 8, and the cylinder chamber 11 ₂
An air exhaust hole 16 is provided in the piping 8.
The heating steam supply pipe 3 is equipped with a solenoid valve 9 and a pressure reducing valve 10.
is adjusted over a range from fully open to fully closed, and the molds 1 and 2 are controlled by the pressure regulating part 4 of this on-off valve 5.
The steam supplied to the chambers 1 ₁ and 2 ₁ is supplied in a pulsating manner so that the steam can easily enter between the beads in the mold, thereby facilitating crushing and foaming of the beads. In this case, pressurized air may be supplied from a pneumatic device and mixed with the steam in the mold chamber.

This pressure regulating section 4 includes a pressure reducing valve 10 and an opening/closing solenoid valve 9.
Valve opening/closing air regulated from the piping 8 enters the cylinder chamber 11 ₁ , secondary steam connected to the molds 1 and 2 flows from the piping 6 to the pressure regulating chamber 13 ₁ , and pressure regulating air enters the cylinder chamber 11 1 from the piping 6. Air is introduced into the pressure adjustment chambers 13 _{and 2} from 7 to 2, and the pressure is adjusted by fluctuations in the balance of these air pressures, but this pulsation is not limited to only one predetermined period, but can be divided into the beginning and end. , or may be applied continuously.

As shown in FIG. 2, the pressure regulating valve consisting of the pressure regulating part 4 and the on-off valve 5 is configured as a normal globe valve, and is designed to move toward and away from the valve seat 20. The pressure part 4 has a constant pressure and a fixed amount of air is connected to the pipe 8.
When the air enters from the valve opening/closing inlet 8 ₁ , the piston 12 is pushed up into the cylinder 11 against the spring 15 , the opening/closing valve 5 is separated from the valve seat 20 , and the steam on the primary side flows into the steam supply pipe 3 . It is designed to flow into the mold through the process. Said on-off valve 5
A connecting member 23 is slidably fitted to the valve shaft ₅₁ .
A diaphragm 13 is provided through the diaphragm 13.

In this case, the diaphragm 13 has a support shaft 22 that is slidably inserted into the connection member 23, and the support shaft 22 connects the regulating valve 1.
4 can be controlled so as to be able to approach and separate from the opening edge of the flow path 17,
The connecting member 23 is a hollow shaft member, and the valve shaft 5 ₁ and the support shaft 22 are slidably fitted from both ends thereof, and the connecting member 23 is movable into the flow path 17 formed in the connecting member 23. The regulating valve 14, which may be enclosed, is also preferably a ball valve.

When steam is supplied to the molds 1 and 2 and the steam pressure inside the molds increases, the steam pressure passes through the piping 6 and enters the pressure regulating chamber 13 ₁ of the diaphragm 13 from the secondary steam pressure inlet 6 _{1 .} If the secondary side steam pressure is lower than the pressure regulating air pressure entering the pressure regulating chamber ₁₃₂ from the pipe 7, the on-off valve 5 is fully open, but the secondary side steam pressure from the pipe 6 As the pressure approaches the pressure regulating air pressure from the piping 7, the balance between the secondary side steam pressure, the pressure regulating air pressure, and the valve opening/closing air pressure collapses, and the valve opening/closing air from the piping 8 flows into the pressurized air flow path 17. It escapes to the outside through the exhaust hole 16 by the regulating valve 14 located at the bottom. As the amount of escaping air increases, the force that was pushing up the on-off valve 5 weakens, and the force of the spring 15 causes the piston 12 to descend, causing the on-off valve 5 to fall and restrict the flow of steam on the primary side. The steam pressure is regulated, the secondary steam pressure is reduced, and the regulating valve 14
is closed, and the pressure in the cylinder chamber ₁₁₁ rises again and moves the on-off valve 5 in the opening direction via the piston 12, but at this time, the on-off valve 5 is opened to a large degree and a large amount of steam (a large amount of heat) is admitted. For mold 1, 2
Because there is a time difference between the internal pressure and the pressure from the air source until the diaphragm 13 is balanced,
The on-off valve 5 moves up and down to give pulsation to the supplied steam, which is then put into the molds 1 and 2, making it easier for the steam to enter between the beads, making it easier to degas by quickly crushing and foaming the beads. , steam can be quickly forced into the mold.

In addition, when heating the molds 1 and 2, the on-off valve 5 is normally closed by a spring 15, but the on-off solenoid valve 9 is opened and operated, and depending on the foam molded product, the steam pressure may be pulsated. If this is not desired, the pressure of the valve opening/closing air from the pipe 8 can be set low using the pressure reducing valve 10 in the pipe 8 to prevent pulsation. However, the heating time for foam molding is slightly longer. For example, when pulsating, the set pressure is 3
~4Kg/ ^cm2 , but when not pulsating,
It becomes 1.5-2.3Kg/ ^cm2 . Furthermore, when performing normal molding, it depends on the expansion ratio, but in the case of 50 to 60 times, the steam pressure may be around 0.5 to 0.8 Kg/cm ² , and the steam pressure will pulsate around ±0.15 Kg/cm ² to the set value. This is effective because it gives Moreover, conventionally the heating time was 15 seconds for the fixed side (female mold) and 10 seconds for the moving side (male mold), but in this example, the heating time was 15 seconds for the fixed side (female mold) and 10 seconds for the moving side (male mold), but in this example
It has become possible to shorten the time to 5 seconds and 4 seconds on the moving side.

Although the exhaust hole 16 in the cylinder 11 is open to the atmosphere, it can also be connected to a muffler or a steam recycling mechanism.

Also, the steam temperature (steam pressure) in the molds 1 and 2
When the diaphragm 13 descends, the diaphragm 13 is pushed down by the pressure regulating air, and the support shaft 22 of the diaphragm 13 presses the regulating valve 14 on the pressurized airflow passage 17, thereby stopping the pressurized air from flowing into the atmosphere. .
As a result, the air pressure below the piston 12 increases, the piston 12 rises against the spring 15, the opening of the on-off valve 5 increases, and a larger amount of steam flows from the heating steam source S into the chambers of the molds 1 and 2. 1 ₁ and 2 ₁ .

[Effect of idea]

This invention is based on expandable thermoplastic resin particles (beads).
After filling the mold, the pressure regulating valve, which is operated by reduced pressure and is interposed in the steam supply path to the chamber part in the male mold and female mold of the foam molding machine that heats the mold with steam and performs foam molding, Consists of an on-off valve with a pressure section, which gives pulsation to the supplied steam, making it easy for the steam to penetrate between the foamable thermoplastic resin particles in the mold, and shortening the supply of heated steam into the mold. The process is carried out smoothly and reliably, and the foaming and bursting of the beads facilitates degassing, which greatly shortens the fusion molding cycle and significantly improves productivity.The temperature of the heating steam can also be easily adjusted, making maintenance and safety easier. This also has the effect of providing a simple and inexpensive configuration.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of the use of an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of the embodiment of the present invention, and FIG. 3 is a longitudinal cross-sectional view of a conventional example. 1...Male mold, 2...Female mold, 3...Steam supply pipe, 4...Pressure adjustment section, 5...Opening/closing valve, 5 ₁ ...
Valve stem, 6... Secondary steam piping, 7... Pressure regulating air piping, 8... Valve opening/closing air piping, 11... Cylinder, 11 ₁ , 11 ₂ ... Cylinder chamber, 12... Piston, 13... ...Diaphragm part, 14...Valve member, 15...Pressure adjustment spring, 16...Air vent hole, 1
7...Flow path, 20...Valve seat, 22...Spindle, 2
3...Connection member.

Claims (1)

[Claims for Utility Model Registration] 1. Chambers 1 ₁ , 2 _{2 of foam molding molds 1 and 2} of a foam molding machine that performs foam molding by heating with steam after filling the mold with expandable thermoplastic resin particles. A pressure regulating valve consisting of a pressure regulating section 4 and an on-off valve 5 provided in a steam supplying section 3 that communicates a heating steam source S and molds 1 and 2 in order to supply heated steam. The part 4 includes a piston 12 provided on the valve shaft 5 ₁ of the on-off valve 5, a cylinder 11 in which the piston 12 is biased in one direction by a spring 15 so as to be slidable, and the piston 1 in the cylinder 11.
It consists of a flow passage 17 that communicates both the cylinder chambers 11 ₁ and 11 ₂ divided by 2, and an adjustment valve 14 that opens and closes the flow passage 17, and the valve shaft 5 ₁ is slidably fitted into the flow passage 17. A connecting member 23, a supporting shaft 22 slidably inserted into the connecting member 23, and a diaphragm 13 for operating the regulating valve 14 in the flow passage 17 with the supporting shaft 22 toward and away from each other are provided. Pressure control chambers divided by 13 ₁ , 13 ₂
One of the pressure regulating chambers 13 ₂ is connected to the pressure regulating air source P via piping 7.
In addition, the other pressure regulating chamber 13 ₁ is connected to the molds 1 and 2.
Further, the cylinder chamber 11 ₁ of the cylinder 11 is connected to the air source P via the valve opening/closing air piping 8, and an air exhaust hole 16 is provided in the cylinder chamber 11 ₂ . A pressure regulating valve for a foam molding machine, characterized in that the on-off valve 5 is constructed as a globe valve. 2. The pressure regulating valve according to claim 1, wherein the connecting member 23 is a hollow shaft member into which the valve shaft ₅₁ and the support shaft 22 are slidably fitted from both ends thereof. 3. Utility model registration according to claim 1 or 2, wherein the regulating valve 14 is a ball valve and is movably enclosed in a flow path 17 formed in the connecting member 23. pressure regulating valve.